High-speed electronic digital computers of the type produced by Cray Research, Inc., the assignee hereof, utilize banks of interconnected circuit modules. Each circuit module typically includes two printed circuit boards mounted on opposite sides of a heat sink (herein referred to as a "cold plate"). Each circuit board in turn includes numerous integrated and discrete circuit, logic, and memory devices. Computers of this type tend to have high circuit densities and numerous input and output signals, connections for which must be provided. Further, the trend is toward computers of greater capacity, increasing circuit densities, and thus even more connections.
A variety of electrical connectors have been available heretofore for use with printed circuit boards, however, there have been certain drawbacks with the prior connectors. The most common approach has been to provide a plug-in type connector consisting of complementary male and female contacts including numerous pins for simultaneously making or breaking multiple contacts. As the number of pin contacts increases, however, the insertion force required to connect the male and female contacts also increases, along with the chances of misalignment and thus damage. It will be appreciated that connectors of this type are not especially tolerant to misalignment and the pins therein can easily become damaged during attempted connection if misaligned even slightly.
U.S. Pat. No. 4,352,533 shows a connector device for printed circuit boards comprising a pair of opposed male portions and an intermediate slideable shuttle portion. The male portions include opposing aligned pins, the pins on one portion being relatively longer than those on the other portion. The female shuttle includes dual entry female contacts which are supported by and moveable along the long pins of one male portion into or out of engagement with the short pins on the other male portion to make or break electrical contact.
On the other hand, the PB 18 printed circuit board connector assembly from ITT Cannon of Mountain Valley, Calif., utilizes a cam for sequentially opening or closing pairs of contacts in zipper fashion. This connector, however, utilizes pre-loaded spring contacts which are normally biased toward engagement with finger contact pads on the edge of the PC board. This type of connector is thus a zero-insertive force-type connector, but relies upon spring tension for surface pressure contact, which is not as reliable as a wiping action type of connection. Further, the slider must be left in place to keep the spring contacts open. This connector also tends to be somewhat bulky.
U.S. Pat. No. 4,700,996, issued to the assignee hereof, illustrates a ZIF type connector utilizing a wiping action type contact. This connector, however, may be improved in a higher connection/density environment. Further, the impedance and other electrical effects of the connector may similarly be improved as the trend toward greater circuit densities and connections increase.
Therefore, there is a need for a new and improved ZIF edge connector of shorter electrical path and controlled impedance wherein electrical contact is established or interrupted sequentially, in either a coaxial or twisted pair environment, utilizing a wiping action type electrical connection, with such connector having greater reliability, alignment and electrical characteristics.